CHICAGO — A woman who helps students go to college with their “posse,” a psychiatrist who treats combat veterans and a museum director on Alaska’s Kodiak Island are among the 24 winners of this year’s MacArthur Foundation “genius grants.”

The $500,000 fellowships were announced Tuesday by the Chicago-based John D. and Catherine T. MacArthur Foundation. Recipients can use the money however they wish.

“It’s an incredible gift,” said Deborah Bial, 42, founder and president of the Posse Foundation, which helps form social networks that college students can turn to for support. “It will change my life and I hope it will change Posse’s life.”

Bial was working with New York City public school students in a leadership program when one of the program’s alumni tried to explain to her why he struggled after high school. “He said, ’I never would have dropped out of college if I had my posse with me,”’ she said.

The conversation inspired Bial, then 23, to create the program that identifies promising teenagers from urban environments and gets them pre-collegiate training in small groups with other students — their “posse” — destined for the same school.

Since then, the New York-based foundation has placed nearly 2,000 students from six cities at 28 colleges. They graduate at a rate of more than 90 percent.

“I feel like the luckiest person in the world because I love what I do,” Bial said. “It was serendipity — I was in the right place at the right time with a kid who had a good idea.”

Since 1981, the MacArthur Foundation has named 756 fellows, recommended to the foundation’s board by a 12-member selection committee.

Other winners of this year’s fellowships include a blues musician, a painter, a playwright, an inventor, a medieval historian, a forensic anthropologist who investigates human rights violations, a biomedical scientist studying how to temporarily reduce metabolism and a spider silk biologist researching new synthetic materials.

Jonathan Fanton, president of the MacArthur Foundation, said he loves calling the new fellows to tell them of their new fellowships.

‘Basic decency’“The basic decency that I hear, the humility, the idealism, just reminds you that for all the bad in the world you read about, there are these great people who have worked hard to make this a more humane, just, fair, peaceful world,” Fanton said.

Anthropologist Sven Haakanson said he at first thought the call notifying him, which woke him one day last week, was a practical joke.

Haakanson, 40, is executive director of the Alutiiq Museum in Alaska. The coastal Alutiiq people are among the native populations of Alaska.

Haakanson, an Alutiiq who grew up on Kodiak, spends seven weeks a year traveling among the island’s villages, working with students and trying to combat a belief that they are “stupid and useless and worthless” because they are a native people — something Haakanson said he struggled with himself.

“It took me eight years at Harvard to figure out I’m not that stupid,” Haakanson said. “I don’t want to create cultural arrogance. I want children to feel good about who they are as humans, give them a culture to celebrate, a heritage to appreciate.”

Marc Edwards, 43, a civil engineering professor at Virginia Tech, was cited for his work helping consumers with water quality problems.

Edwards is quick to credit the students who help him with his work. One of them, Jarrett Lane, was killed April 16 when Seung-Hui Cho killed 32 people and himself on the Virginia Tech campus.

“Not a day goes by that we don’t think about (Lane) or our other colleagues,” Edwards said.

Edwards was on campus that day but prefers not to share any details of his personal experience. “It brought us all together in a very positive way in the aftermath,” he said.

Another fellow is Dr. Jonathan Shay, a staff psychiatrist at the Department of Veterans Affairs outpatient clinic in Boston. His two books — “Achilles in Vietnam: Combat Trauma and the Undoing of Character” and “Odysseus in America: Combat Trauma and the Trials of Homecoming” — employ ancient heroes to help understand the effects of war on individuals.

Shay, 65, is an advocate for choices he believes can be made before soldiers are deployed to aid their psychiatric well-being.

“War is war is war is war,” Shay said. “... What’s important about it is not what makes it unique, but what makes it a universal experience for the returning soldiers.”